Drainages

Napa Valley American Viticultural Area (AVA) This layer is composed of a polygon that depicts the land in Napa VALLEY that is part of the Napa Valley Viticultural Area

Rivers, streams and drainage network of Ethiopia showing the extent and hierarchy of surface water features. Use this layer for watershed analysis, flood modelling, irrigation planning, water resource mapping, and environmental impact assessment.

Full Metadata This EnviroAtlas web service supports research and online mapping activities related to EnviroAtlas (https://www.epa.gov/enviroatlas). This web service includes layers depicting depicting NHD Version 2.1 Plus flowlines and waterbodies for the conterminous United States. Flowlines are separated out to display 3rd Order and smaller flowline features in one layer and 4th Order and higher flowline features in another. EnviroAtlas allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the conterminous United States as well as detailed metrics for select communities. Additional descriptive information about each attribute in this web service can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

The Streams GIS Layer contains data sourced from National Hydrography Dataset.

The rivers of North America dataset is derived from the World Wildlife Fund's (WWF) HydroSHEDS drainage direction layer and a stream network layer. The source of the drainage direction layer was the 15-second Digital Elevation Model (DEM) from NASA's Shuttle Radar Topographic Mission (SRTM). The raster stream network was determined by using the HydroSHEDS flow accumulation grid, with a threshold of about 1000 km² upstream area. The stream network dataset consists of the following information:- unique arc identifier (ARCID), the origin node of each arc in the network (FROM_NODE), the destination of each arc in the network (TO_NODE), the Strahler stream order of each arc in the network (STRAHLER), numerical code and name of the major basin that the arc falls within (MAJ_BAS and MAJ_NAME); - area of the major basin in square km that the arc falls within (MAJ_AREA); - numerical code and name of the sub-basin that the arc falls within (SUB_BAS and SUB_NAME); - area of the sub-basin in square km that the arc falls within (SUB_AREA); - numerical code of the sub-basin towards which the sub-basin flows that the arc falls within (TO_SUBBAS) (the codes -888 and -999 have been assigned respectively to internal sub-basins and to sub-basins draining into the sea). **Data revision:** 2014-03-05 **Supplemental Information:** This dataset is developed as part of a GIS-based information system on water resources for North America. It has been published in the framework of the AQUASTAT - programme of the Land and Water Division of the Food and Agriculture Organization of the United Nations. The attributes table now includes a field named "Regime" with tentative classification of perennial ("P") and intermittent ("I") streams. **Time coverage**: 2014 **Contact points:** Resource Contact: [Jippe Hoogeveen](mailto:jippe.hoogeveen@fao.org) Resource Contact: [Livia Peiser](mailto:livia.peiser@fao.org) Metadata Contact: [AQUASTAT](mailto:aquastat@fao.org) **Data lineage:** The linework of the map was obtained by converting the stream network to a feature dataset with the Hydrology toolset in ESRI ArcGIS.The Flow Direction and Stream Order grids were derived from hydrologically corrected elevation data with a resolution of 15 arc-seconds.The elevation dataset was part of a mapping product, HydroSHEDS, developed by the Conservation Science Program of World Wildlife Fund.Original input data had been obtained during NASA's Shuttle Radar Topography Mission (SRTM). **Resource constraints:** This work is made available under the Creative Commons Attribution 4.0 International licence (CC-BY-4.0) **Online resources:** Download - Rivers of Nortn America (ESRI shapefile) Technical information on the data source More updated information on HydroSHEDS 2025

Full Metadata This EnviroAtlas web service supports research and online mapping activities related to EnviroAtlas (https://www.epa.gov/enviroatlas). This web service includes layers depicting depicting NHD Version 2.1 Plus flowlines and waterbodies for the conterminous United States. Flowlines are separated out to display 3rd Order and smaller flowline features in one layer and 4th Order and higher flowline features in another. EnviroAtlas allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the conterminous United States as well as detailed metrics for select communities. Additional descriptive information about each attribute in this web service can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).